1. Field of The Invention This invention relates to an instrument for accessing the laryngeal area of the human body and, more particularly, to an improved laryngoscope having a blade with a removable leaf.
2. Prior Art Laryngoscopes are widely known and used in the medical field to facilitate endotracheal intubation of a patient during surgery to provide a positive air passageway for the administration of anesthesia and/or for the mechanical ventilation of the lungs of the patient. In the human anatomy, the epiglottis normally overlies the glottis opening into the larynx to prevent the passage of food into the trachea during eating; therefore, in endotracheal intubation, it is necessary to displace the epiglottis from the glottal opening to permit the air tube to be inserted into the trachea.
Various laryngoscope constructions are known. The more widely used laryngoscopes consist of an elongate, rigid metal blade which is supportably attached to a handle and is inserted through the mouth of the patient into the pharyngeal area to displace the tongue and epiglottis and permit direct visualization of the glottis through the mouth opening. Such laryngoscopes are generally provided with a light source which is directed along the blade to illuminate the area beyond the distal end of the blade. Two general types of rigid blade constructions are the straight, or so called "Miller blade", and the slightly curved, or so called "MacIntosh blade." Curved laryngoscope blade constructions having light means to facilitate illumination of the areas of observation are described in U.S. Pat. Nos. 3,598,113; 3,643,654; 3,766,909; and 3,771,514.
The standard method for performing intubation of the trachea during surgery with rigid laryngoscope blades of the straight or slightly curved type is to place the patient in a supine position, tilt the head backwards as far as possible, and distend the lower jaw to widely open the mouth. The rigid blade is then inserted through the mouth into the throat passageway to displace the tongue and epiglottis and expose the glottis of the patient. The larynx is then viewed through the mouth opening from an observation position just above and behind the head of the patient by sighting generally along the axis of the blade. The endotracheal tube is inserted, either orally or transnasally, and passed alongside the blade through the glottis.
Surgical instruments having means for indirect illumination and visualization of the pharyngeal areas of the body are known. U.S. Pat. Nos. 3,776,222 and 3,913,568 disclose devices for endotracheal intubation which comprise flexible or articulatable tubular probes having internal fiber optics for lighting and viewing the internal areas of the body. As disclosed in said patents, the probes carry a slidably removable endotracheal tube surrounding their outer surfaces and the probe is directly inserted into the trachea to position the tube. Such devices obviously require the use of relatively large diameter endotracheal tubes in order to be carried on the tubular probe, and their use necessarily is limited to patients with sufficiently large airway passages to accommodate the combined size of the probe and endotracheal tube. Additionally, due to the flexible nature of the probes, it is difficult to manipulate the probe to displace the tongue and epiglottis to permit direct insertion of the tube into the trachea.
U.S. Pat. No. 2,354,471 by MacIntosh discloses a laryngoscope having a handle and hinged blade to facilitate the exposure of the larynx to pass an endotracheal tube. U.S. Pat. No. 3,643,654 by Felbarg discloses a laryngoscope comprised of a tubelike member adapted to be mounted on a conventional handle. U.S. Pat. No. 3,766,909 by Ozbey discloses a laryngoscope with a disposable blade and light guide. U.S. Pat. No. 4,527,553 by Upsher discloses a laryngoscope having a blade and separate handle.
However, a problem exists with the devices known in the prior art in that no device is provided for indirect illumination and visualization of the pharyngeal areas of the body which has a blade comprising a relatively fixed shaft or stem with a removable tongue petal or leaf.
A further problem exists with the devices in the prior art in that no means are provided for mounting alternative or interchangable types of tongue leafs with a laryngoscope having a relatively fixed shaft.
A further problem exists in the devices known in the prior art in that different devices having different types of blades must be used for different applications.